Protect films or adhesives containing a polyolefinic material as a base material are inexpensive, and therefore have been variously studied in the past. For example, PTL 1 discloses a protect film produced by mixing a liquid polybutene or a polyisobutylene as a tackifier with an ethylenic polymer. Further, PTL 2 discloses an adhesive tape composed of an olefin polymer and an adhesive resin.